Objective: To gain Dutch population norms for the Short Form-12 (SF-12), a generic health status questionnaire, in a random sample of the general population and to validate these in postmyocardial infarction (MI) patients.
Methods: 2,301 respondents from the general population and 459 post-MI patients completed the Short Form-36 (SF-36), which was used to calculate SF-12 scores.
Results: The SF-12 summary scores correlated highly with SF-36 summary scores, demonstrating that these scores explain the same amount of variance in health status. Significant sex differences (P < .001) existed for both the physical component summary (PCS) and the mental component summary (MCS). Multivariate analysis of variance showed a main effect of age in oblique (PCS-12: P < .001; MCS-12: P < .001) and orthogonally rotated PCS scores (PCS-12_uc: P < .001; MCS-12_uc: P = .07). As expected, post-MI patients reported statistically significant and clinically relevant poorer mental (P < .001) and physical functioning (P < .001). Differences were less pronounced for MCS and PCS derived from orthogonal rotation data. When controlling for covariates, MI did not significantly affect PCS-12_uc anymore in orthogonally rotated data, while PCS-12_uc was affected by fewer covariates compared with PCS-12.
Conclusions: This study presents Dutch population norms for the SF-12 in a large random population sample obtained from both oblique and orthogonal PCA rotation methods, revealing systematic differences between the results based on these two methods. Furthermore, this study demonstrates the discriminative validity of the SF-12 by showing that post-MI patients differ significantly from the normative population on PCS-12 scores.